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April 9, 2009
7051-158
Page 9
EDGE 60 Pellet Fireplace
Negative pressure results from the imbalance of air avail
-
able for the fireplace to operate properly. It can be strongest
in lower levels of the house.
Causes include:
• Exhaust fans (kitchen, bath, etc.)
• Range hoods
• Combustion air requirements for furnaces, water heaters
and other combustion appliances
• Clothes dryers
• Location of return-air vents to furnace or air conditioning
• Imbalances of the HVAC air handling system
• Upper level air leaks such as:
- Recessed lighting
- Attic hatch
- Duct leaks
To minimize the effects of negative air pressure:
• Install the outside air kit with the intake facing prevailing
winds during the heating season
• Ensure adequate outdoor air for
all
combustion appliances
and exhaust equipment
• Ensure furnace and air conditioning return vents are not
located in the immediate vicinity of the fireplace
• Avoid installing the appliance near doors, walkways or
small isolated spaces
• Recessed lighting should be a “sealed can” design
• Attic hatches weather stripped or sealed
• Attic mounted duct work and air handler joints and seams
taped or sealed
WARNING! Risk of Asphyxiation!
Negative pressure can
cause spillage of combustion fumes and soot.
C. Negative Pressure
Draft is the pressure difference needed to vent fireplaces
successfully. When a fireplace is drafting successfully, all
combustion byproducts are exiting the home through the
chimney.
Install through the warm airspace enclosed by the building
envelope. This helps to produce more draft, especially dur
-
ing lighting and die-down of the fire.
Considerations for successful draft include:
• Preventing negative pressure
• Location of fireplace and chimney
NOTICE:
Hearth & Home Technologies assumes no
responsibility for the improper performance of the chimney
system caused by:
• Inadequate draft due to environmental conditions
• Downdrafts
• Tight sealing construction of the structure
• Mechanical exhausting devices
D. Draft